Constantly being transferred to cover other staff

Heres one you folks might know and to begin, its not for me. Im covered by my own employment conditions but this is private sector and Im not as confident

Basically, I know a person who due to covid had their shop closed and was put on covid payment. When shops started to reopen they put her in an alternative shop for a few months then put back to the city centre but in an alternative shop.

After another month, the city centre shop manager meandered back after isolating (he went home while it was closed). Since then hes being gradually bringing his own staff back and the temp people are being put to other premises or back on covid.

The issue is, my friend keeps getting sent from A to B to C at **** all notice to cover staff holidays, isolating or whatever.

She didnt mind at the start but is getting pissed off never knowing where she will be next week, what shifts or who to clear holidays with and when she does land somewhere, they moan that shes looking for days off because shes only there to cover staff shortages.

For my part, I think she should be looking for travel money at this stage. She is employed in shop A afterall and lives in that area as a result. Sadly she didnt think to keep her contract so Im unsure whats in it. I know a transfer clause is usual in chains but surely not constant transfers?